Airflow Sensor question - PeachParts Mercedes-Benz Forum

d2bernhard · #1 09-14-2002, 08:13 PM

Today I conked out in traffic and had to tow home. Was getting ready to replace the Fuel Distributor, as the dealer diagnosed this as bad yesterday, and I noticed the airflow sensor plate was stuck (up). Pushed and it popped open and moves freely now. Also cleaned some grime off it. Has anyone ever seen this? Will this continue to get worse — is this a symptom of it failing -- or does everyone think this is a fluke?

And also, there is an eletrical connector, two prong, that goes onto a little black box on the side (aft) of the fuel distrubutor. What does that do? What happens if it is not plugged back in by the (grit my teath) dealer after they are done testing the damn thing?

Many Thanks,

I am saving my Fuel Distributor job for another time, but I have the part. (My first TWO cars cost less than that sucker!)

d2bernhard · #2 09-17-2002, 12:22 PM

I know this is somewhat shameless to move this to the top, but have I stumped everyone?

I had cranked the car a few times with no start. Could this have jammed the airflow plate up?

Thnaks

190dee · #3 09-17-2002, 12:38 PM

Could this be caused by bad alignment? I have seen pics of this in some books but never in real life. That would just give you another question; what may have caused the movement of sensor to a "offset" position.

Have you got pics of the jammed sensor? I'm sure that would give the thread some sparks...

I would want anyone to second me on this since I only read about the fuel distributor. Anyway, the black thing is adjusting the chamber pressure. If it isn't plugged in the car won't work because you'll never get the right pessure in the chambers. It should definetly be plugged if you want the car to start. The amount of fuel that gets distributed is adjusted by the amps flowing thru here...No amperes, no fuel for the engine.

But I suggest you get some other member on the forum to second before you do anything about it.

d2bernhard · #4 09-17-2002, 02:10 PM

I don't have pictures, and it is not longer stuck. I pushed it down and the it seems to work fine. I pushed gently but firmly, about 2-6 lbs of force ... and it popped open.

vrsmith · #5 09-17-2002, 02:28 PM

Can you hear the fuel pump when you turn on the key? The airflow
meter might not be the only problem, especially since you might have unstuck it.

190dee · #6 09-17-2002, 02:29 PM

The plate itself shouldn't touch the inner walls. If it does something isn't right. Could be just a alignment, could be something else...

Did you plug the wires already or are you waiting for confirmation on the distributor?! I could do some research in my "bosch fuel injection bible"...

d2bernhard · #7 09-17-2002, 04:23 PM

Hold the phone! Car Runs!!

Last Saturday, I freed the plate, plugged in the connector back into the fuel distro, and car runs like it always has -- rough idle, hesitation, Difficult hot start, and intermittent stumble at cruise. Dealer said it needs the fuel distro (per MB spec tests). If anyone can give me less expensive things to look at, I'd be grateful.

Replaced:
OVP
Pump relay
Fuel filter
Cap & Rotor
Plugs & Wires
Air Filter
All fluids
Considering Fuel Pump Check Valve and Accumulator.

Did a double shot of dry gas last night (1 bottle treats 10-20 gallons, so I put in 2) -- seems to help??! I've heard about moisture in the fuel distro. Can dry gas get it out?

d2bernhard · #8 01-17-2005, 06:51 PM

Hi All. Bumping this again. Car has been running (quite well, I might add) since a few weeks after this last post in Sept '02. Kinda all of a sudden something got blasted out and all is well except hot start trouble, and lately more and more fuel stink. Does this sound like EHA valve troubles?

John Plut · #9 01-17-2005, 10:07 PM

The fuel smell you describe could be caused by a leaky EHA or fuel distributor o-ring seal. It sounds to me like your EHA might be causing some funky compensating pressures that are causing your running problems. I replaced mine because it was leaking slightly and it cleared up a hesitation and two-start problem too.